1. Field of the Invention
The present invention relates to a passivation layer assembly on a substrate and a display substrate having the passivation layer assembly. More particularly, the present invention relates to a passivation layer assembly on a substrate that is capable of decreasing the malfunction rate of a display device, and a display substrate having the passivation layer assembly.
2. Description of the Related Art
An electronic device such as a cellular phone, a digital camera, a notebook computer, a monitor, etc., includes a display device that displays an image based on an image signal from a separate component that is connected to the display device. There are many types of display devices, some examples of which are a cathode ray tube (CRT) device, a liquid crystal display (LCD) device, a plasma display panel (PDP) device, a field emission display (FED) device, an organic light emitting display (OLED) device, etc.
Of the numerous types of display devices, the LCD device has advantageous characteristics such as its compactness, thinness, lightness, low power consumption, low driving voltage, etc. An LCD device displays images using electrical and optical characteristics of liquid crystals.
The LCD device includes a display panel that displays images using the light transmittance property of the liquid crystals. The display panel includes a first substrate, a second substrate, and a liquid crystal layer between the first and second substrates. The first substrate includes a plurality of thin film transistors (TFTs). The second substrate includes a color filter. The liquid crystal layer is interposed between the first and second substrates.
The first substrate further includes an insulating layer on the TFTs and a pixel electrode that is electrically connected to each of the TFTs. The insulating layer has a contact hole through which each of the TFTs is electrically connected to the pixel electrode. The insulating layer is partially etched using an etchant, to form the contact hole.
When a vertical profile of the contact hole is irregular, the TFT is disconnected from the pixel electrode to generate a malfunction of the LCD device.